OpenBSD/Disk formatting

This is how you can format a disk on OpenBSD:

Use sysctl hw.disknames or dmesg | grep sd to find the names of attached disks.
Then, run disklabel -E sdX where X is the name of the connected disk you want to edit (MAKE SURE YOU HAVE IT RIGHT!)
Enter z to delete the existing partition table. Then type a to add a partition. Afterwards w and then q to save and quit.
After this is done you will be left with a partition called sdXa. (a is the root partition in the bsd disklabel scheme) Run newfs sdXa to format it.

See also